1.
Near-Earth object
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A near-Earth object is any small Solar System body whose orbit brings it into proximity with Earth. By definition, a solar system body is a NEO if its closest approach to the Sun is less than 1.3 astronomical unit and it is now widely accepted that collisions in the past have had a significant role in shaping the geological and biological history of the Earth. NEOs have become of increased interest since the 1980s because of increased awareness of the potential danger some of the asteroids or comets pose, and mitigations are being researched. In January 2016, NASA announced the Planetary Defense Coordination Office to track NEOs larger than 30 to 50 meters in diameter and coordinate an effective threat response, NEAs have orbits that lie partly between 0.983 and 1.3 AU away from the Sun. When a NEA is detected it is submitted to the IAUs Minor Planet Center for cataloging, some NEAs orbits intersect that of Earths so they pose a collision danger. The United States, European Union, and other nations are currently scanning for NEOs in an effort called Spaceguard. In the United States and since 1998, NASA has a mandate to catalogue all NEOs that are at least 1 kilometer wide. In 2006, it was estimated that 20% of the objects had not yet been found. In 2011, largely as a result of NEOWISE, it was estimated that 93% of the NEAs larger than 1 km had been found, as of 5 February 2017, there have been 875 NEAs larger than 1 km discovered, of which 157 are potentially hazardous. The inventory is much less complete for smaller objects, which still have potential for scale, though not global. Potentially hazardous objects are defined based on parameters that measure the objects potential to make threatening close approaches to the Earth. Mostly objects with an Earth minimum orbit intersection distance of 0.05 AU or less, objects that cannot approach closer to the Earth than 0.05 AU, or are smaller than about 150 m in diameter, are not considered PHOs. This makes them a target for exploration. As of 2016, three near-Earth objects have been visited by spacecraft, more recently, a typical frame of reference for looking at NEOs has been through the scientific concept of risk. In this frame, the risk that any near-Earth object poses is typically seen through a lens that is a function of both the culture and the technology of human society, NEOs have been understood differently throughout history. Each time an NEO is observed, a different risk was posed and it is not just a matter of scientific knowledge. Such perception of risk is thus a product of religious belief, philosophic principles, scientific understanding, technological capabilities, and even economical resourcefulness.03 E −0.4 megatonnes. For instance, it gives the rate for bolides of 10 megatonnes or more as 1 per thousand years, however, the authors give a rather large uncertainty, due in part to uncertainties in determining the energies of the atmospheric impacts that they used in their determination

2.
Asteroid belt
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The asteroid belt is the circumstellar disc in the Solar System located roughly between the orbits of the planets Mars and Jupiter. It is occupied by numerous irregularly shaped bodies called asteroids or minor planets, the asteroid belt is also termed the main asteroid belt or main belt to distinguish it from other asteroid populations in the Solar System such as near-Earth asteroids and trojan asteroids. About half the mass of the belt is contained in the four largest asteroids, Ceres, Vesta, Pallas, the total mass of the asteroid belt is approximately 4% that of the Moon, or 22% that of Pluto, and roughly twice that of Plutos moon Charon. Ceres, the belts only dwarf planet, is about 950 km in diameter, whereas Vesta, Pallas. The remaining bodies range down to the size of a dust particle, the asteroid material is so thinly distributed that numerous unmanned spacecraft have traversed it without incident. Nonetheless, collisions between large asteroids do occur, and these can form a family whose members have similar orbital characteristics. Individual asteroids within the belt are categorized by their spectra. The asteroid belt formed from the solar nebula as a group of planetesimals. Planetesimals are the precursors of the protoplanets. Between Mars and Jupiter, however, gravitational perturbations from Jupiter imbued the protoplanets with too much energy for them to accrete into a planet. Collisions became too violent, and instead of fusing together, the planetesimals, as a result,99. 9% of the asteroid belts original mass was lost in the first 100 million years of the Solar Systems history. Some fragments eventually found their way into the inner Solar System, Asteroid orbits continue to be appreciably perturbed whenever their period of revolution about the Sun forms an orbital resonance with Jupiter. At these orbital distances, a Kirkwood gap occurs as they are swept into other orbits. Classes of small Solar System bodies in other regions are the objects, the centaurs, the Kuiper belt objects, the scattered disc objects, the sednoids. On 22 January 2014, ESA scientists reported the detection, for the first definitive time, of water vapor on Ceres, the detection was made by using the far-infrared abilities of the Herschel Space Observatory. The finding was unexpected because comets, not asteroids, are considered to sprout jets. According to one of the scientists, The lines are becoming more and more blurred between comets and asteroids. This pattern, now known as the Titius–Bode law, predicted the semi-major axes of the six planets of the provided one allowed for a gap between the orbits of Mars and Jupiter

3.
Apache Point Observatory
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The Apache Point Observatory is an astronomical observatory located in the Sacramento Mountains in Sunspot, New Mexico, United States, approximately 18 miles south of Cloudcroft. The observatory is operated by New Mexico State University and owned by the Astrophysical Research Consortium, access to the telescopes and buildings is restricted, but the public is able to visit the grounds. The ARC was formed in 1984 with the goal of building the 3.5 m telescope, five additional organizations have joined over time, the Institute for Advanced Study, Johns Hopkins University, University of Colorado, University of Virginia, and Georgia State University. Funding for the 3.5 m and 0.5 m telescopes comes from consortium, the 1.0 m telescope is supported exclusively by NMSU. The ARC3.5 m telescope is a Ritchey-Chretien reflector on a mount with instruments attached at several focal points. Construction of the began in 1985, but full operations of the telescope were delayed until November 1994 due to problems with fabricating the primary mirror. From 1991 until early 1993 the telescope was fitted with a 1.8 m mirror now located at Rothney Astrophysical Observatory under a cost-sharing agreement. There are a variety of optical and near-infrared instruments available for the 3.5 m telescope, including, the Double Imaging Spectrometer is a low-resolution optical spectrometer. The Near Infrared Camera/Fabry–Pérot Spectrometer was developed at the University of Colorado and it uses a 1024x1024 H1RG HgCdTe infrared detector and a near-infrared Fabry–Pérot interferometer. It has many narrow band filters, including H2, and and it is unique among astronomical Fabry-Pérot devices in that it is cooled with liquid nitrogen. The Seaver Prototype Imaging camera is an imaging instrument with a 2048x2048 pixel CCD. TripleSpec is a near infrared spectrograph which provides continuous coverage over the range 0. 94-2.46 µm at moderate resolution. The 3.5 m telescope is used by the Apache Point Observatory Lunar Laser-ranging Operation lunar-ranging project. The APOLLO laser has been operational since October 2005, and routinely accomplishes millimeter-level range accuracy between the Earth and the Moon, observations using the 3.5 m telescope can be carried out remotely by observers using TUI, the Telescope User Interface, via the internet. The SDSS2.5 m telescope is used for the Sloan Digital Sky Survey and it is a Ritchey-Chretien reflector on an alt-azimuth mount housed under a roll-off enclosure. It was designed with an unusually large 3° field of view to support its primary task of surveying the entire sky. The NMSU1.0 m telescope is a Ritchey-Chretien reflector set on an alt-azimuth mount, a 2048x2048 CCD mounted at the Nasmyth focus provides at 15.7 arcminute view of the sky. The ARC Small Aperture Telescope was previously called the Photometric Telescope when it was part of the SDSS project and it is a 0.5 m reflecting telescope on an equatorial mount, with a single CCD camera cooled by a CryoTiger unit

4.
Sloan Digital Sky Survey
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The project was named after the Alfred P. Sloan Foundation, which contributed significant funding. Data collection began in 2000, and the imaging data release covers over 35% of the sky, with photometric observations of around 500 million objects. Data release 8, released in January 2011, includes all photometric observations taken with the SDSS imaging camera, covering 14,555 square degrees on the sky. Data release 9, released to the public on 31 July 2012, includes the first results from the Baryon Oscillation Spectroscopic Survey spectrograph, over 500,000 of the new spectra are of objects in the Universe 7 billion years ago. DR10 also includes over 670,000 new BOSS spectra of galaxies, the publicly available images from the survey were made between 1998 and 2009. SDSS uses a dedicated 2. 5-m wide-angle optical telescope, from 2000-2009 it observed in both imaging and spectroscopic modes, the imaging camera was retired in late 2009, since when the telescope has observed entirely in spectroscopic mode. Images were taken using a system of five filters. For imaging observations, the SDSS telescope used the drift scanning technique and this method allows consistent astrometry over the widest possible field, and minimises overheads from reading out the detectors. The disadvantage is minor distortion effects, the telescopes imaging camera is made up of thirty CCD chips each with a resolution of 2048×2048 pixels, totaling approximately 120 Megapixels. The chips are arranged in five rows of six chips, the filters are placed on the camera in the order r, i, u, z, g. To reduce noise the camera is cooled to 190 kelvin by liquid nitrogen, using these photometric data, stars, galaxies, and quasars are also selected for spectroscopy. The spectrograph operates by feeding an optical fibre for each target through a hole drilled in an aluminum plate. Each hole is positioned specifically for a target, so every field in which spectra are to be acquired requires a unique plate. The original spectrograph attached to the telescope was capable of recording 640 spectra simultaneously, over the course of each night, between six and nine plates are typically used for recording spectra. In spectroscopic mode, the tracks the sky in the standard way. Every night the telescope produces about 200 GB of data and it also obtained repeated imaging of a 300 square degree stripe in the southern Galactic cap. The survey covers over 7,500 square degrees of the Northern Galactic Cap with data from nearly 2 million objects and spectra from over 800,000 galaxies and 100,000 quasars. The information on the position and distance of the objects has allowed the structure of the Universe, with its voids and filaments

5.
Jupiter trojan
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The Jupiter trojans, commonly called Trojan asteroids or just Trojans, are a large group of asteroids that share the orbit of the planet Jupiter around the Sun. Relative to Jupiter, each Trojan librates around one of Jupiters two stable Lagrangian points, L4, lying 60° ahead of the planet in its orbit, and L5, 60° behind. Jupiter trojans are distributed in two elongated, curved regions around these Lagrangian points with an average axis of about 5.2 AU. The first Jupiter trojan discovered,588 Achilles, was spotted in 1906 by German astronomer Max Wolf, a total of 6,178 Jupiter trojans have been found as of January 2015. By convention they are named after a mythological figure from the Trojan War. The total number of Jupiter trojans larger than 1 km in diameter is believed to be about 1 million, like main-belt asteroids, Jupiter trojans form families. Jupiter trojans are bodies with reddish, featureless spectra. The Jupiter trojans densities vary from 0.8 to 2.5 g·cm−3, Jupiter trojans are thought to have been captured into their orbits during the early stages of the Solar Systems formation or slightly later, during the migration of giant planets. NASA has announced the discovery of an Earth trojan, the trapped body will librate slowly around the point of equilibrium in a tadpole or horseshoe orbit. These leading and trailing points are called the L4 and L5 Lagrange points, however, no asteroids trapped in Lagrange points were observed until more than a century after Lagranges hypothesis. Those associated with Jupiter were the first to be discovered, E. E. Barnard made the first recorded observation of a Trojan,1999 RM11, in 1904, but neither he nor others appreciated its significance at the time. Barnard believed he saw the recently discovered Saturnian satellite Phoebe, which was only two away in the sky at the time, or possibly an asteroid. The objects identity was not realized until its orbit was calculated in 1999, in 1906–1907 two more Jupiter trojans were found by fellow German astronomer August Kopff. Hektor, like Achilles, belonged to the L4 swarm, whereas Patroclus was the first asteroid known to reside at the L5 Lagrangian point, by 1938,11 Jupiter trojans had been detected. This number increased to 14 only in 1961, as instruments improved, the rate of discovery grew rapidly, by January 2000, a total of 257 had been discovered, by May 2003, the number had grown to 1,600. Asteroids in the L4 group are named after Greek heroes, confusingly,617 Patroclus was named before the Greece/Troy rule was devised, and a Greek name thus appears in the Trojan node. The Greek node also has one misplaced asteroid,624 Hektor, estimates of the total number of Jupiter trojans are based on deep surveys of limited areas of the sky. The L4 swarm is believed to hold between 160–240,000 asteroids with diameters larger than 2 km and about 600,000 with diameters larger than 1 km

6.
Socorro, New Mexico
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Socorro is a city in Socorro County in the U. S. state of New Mexico. It is in the Rio Grande Valley at an elevation of 4,579 feet, in 2012 the population was 8,906. It is the county seat of Socorro County, Socorro is located 74 miles south of Albuquerque and 146 miles north of Las Cruces. In June 1598, Juan de Oñate led a group of Spanish settlers through the Jornada del Muerto, as the Spaniards emerged from the desert, Piro Indians of the pueblo of Teypana gave them food and water. Therefore, the Spaniards renamed this pueblo Socorro, which means help or aid, later, the name Socorro would be applied to the nearby Piro pueblo of Pilabó. Nuestra Señora de Perpetuo Socorro, the first Catholic mission in the area, was established c. Fray Agustín de Vetancurt would later write that around 600 people lived in the area during this period, Mines in the Socorro mountains were opened by 1626. During the Pueblo Revolt of 1680, Spanish refugees stopped in the pueblo of Socorro, a number of Piro Indians followed the Spaniards as they left the province to go south to safety. With no protection of Spanish troops, Socorro was destroyed and the remaining Piro were killed by the Apache, the Spanish did not initially resettle Socorro when they re-conquered New Mexico. Other than El Paso, there were no Spanish settlements south of Sabinal until the 1800s, in 1800, governor Fernando Chacon gave the order to resettle Socorro and other villages in the area. However, Socorro was not resettled until about 1815, in 1817,70 Belen residents petitioned the crown for land in Socorro. The 1833 Socorro census lists over 400 residents, with a total of 1,774 people living within the vicinity of the village, the mission of San Miguel de Socorro was established soon after Socorro was resettled. The church was built on the ruins of the old Nuestra Señora de Socorro, in August 1846, during the Mexican–American War, New Mexico was occupied by the American Army. In Las Vegas, New Mexico, Colonel Stephen W. Kearny proclaimed New Mexicos independence from Mexico, on their way to begin their assault on Mexico, American troops stopped in Socorro. A British officer, Lt. George Ruxton, commented that these soldiers were unwashed and unshaven, were ragged and dirty, in September 1850, New Mexico became a territory of the United States. At the time, New Mexico encompassed what is now the states of New Mexico, in 1850, the population of Socorro was only 543 people. This included 100 American soldiers who were moved to Valverde. The first military post built near Socorro was Fort Conrad,30 miles south of the town, built in August 1851, the fort was badly constructed and was abandoned for Fort Craig, located a few miles away

7.
Palomar Observatory
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Palomar Observatory is an astronomical observatory located in San Diego County, California, United States,145 kilometers southeast of Los Angeles, California, in the Palomar Mountain Range. It is owned and operated by the California Institute of Technology located in Pasadena, research time is granted to Caltech and its research partners, which include the Jet Propulsion Laboratory and Cornell University. The observatory operates several telescopes, including the famous 200-inch Hale Telescope, astronomer George Ellery Hale, whose vision created the Palomar Observatory, built the worlds largest telescope four times. He published an article in the April 1928 issue of Harpers Magazine called The Possibilities of Large Telescopes, Hale hoped that the American people would understand and support his project. Hale followed this article with a letter to the International Education Board of the Rockefeller Foundation dated April 28,1928, in his letter, Hale stated, No method of advancing science is so productive as the development of new and more powerful instruments and methods of research. The 200-inch telescope is named after astronomer George Hale and it was built by Caltech with a $6 million grant from the Rockefeller Foundation, using a Pyrex blank manufactured by Corning Glass Works. Anderson was the project manager assigned in the early 1940s. The telescope saw first light January 26,1949 targeting NGC2261, the American astronomer Edwin Powell Hubble, perhaps the most important observer of the 20th century, was given the honor of being the first astronomer to use the telescope. Astronomers using the Hale Telescope have discovered distant objects at the edges of the universe called quasars and have given us the first direct evidence of stars in distant galaxies. They have studied the structure and chemistry of intergalactic clouds, leading to an understanding of the synthesis of elements in the universe, porter worked on the designs in collaboration with many engineers and Caltech committee members. The gleaming white building on Palomar Mountain that houses the 200–inch Hale Telescope is considered by many to be The Cathedral of Astronomy, the 200-inch Hale Telescope was first proposed in 1928 and has been operational since 1948. It was the largest telescope in the world for 45 years, a 60-inch reflecting telescope is located in the Oscar Mayer Building. It was dedicated in 1970 to take some of the load off of the Hale Telescope and this telescope was used to discover the first brown dwarf star. The 48-inch Samuel Oschin Telescope was started in 1938 and installed in 1948 and it was initially called the 48–inch Schmidt, and was dedicated to Samuel Oschin in 1986. The dwarf planet Eris was discovered using this instrument, the existence of Eris triggered the discussions in the international astronomy community that led to Pluto being re-classified as a dwarf planet. An 18-inch Schmidt camera became the first operational telescope at the Palomar in 1936, in the 1930s, Fritz Zwicky, a Caltech astronomer, discovered over 100 supernovae in other galaxies with this telescope and gathered the first evidence for dark matter. Comet Shoemaker-Levy 9 was discovered with this instrument in 1993 and it has since been retired and is on display at the small museum/visitor center. The Palomar Testbed Interferometer was an instrument that permitted astronomers to make very high resolution measurements of the sizes

8.
Asteroid family
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An asteroid family is a population of asteroids that share similar proper orbital elements, such as semimajor axis, eccentricity, and orbital inclination. The members of the families are thought to be fragments of past asteroid collisions, an asteroid family is a more specific term than asteroid group whose members, while sharing some broad orbital characteristics, may be otherwise unrelated to each other. Large prominent families contain several hundred recognized asteroids, small, compact families can have only about ten identified members. About 33% to 35% of asteroids in the belt are family members. There are about 20 to 30 reliably recognized families, with tens of less certain groupings. One family has been identified associated with the dwarf planet Haumea, some studies have tried to find evidence of collisional families among the trojan asteroids, but at present the evidence is inconclusive. The families are thought to form as a result of collisions between asteroids, in many or most cases the parent body was shattered, but there are also several families which resulted from a large cratering event which did not disrupt the parent body. Such cratering families typically consist of a large body and a swarm of asteroids that are much smaller. Some families have complex structures which are not satisfactorily explained at the moment. Due to the method of origin, all the members have closely matching compositions for most families, notable exceptions are those families which formed from a large differentiated parent body. Asteroid families are thought to have lifetimes of the order of a billion years and this is significantly shorter than the Solar Systems age, so few if any are relics of the early Solar System. Such small asteroids then become subject to such as the Yarkovsky effect that can push them towards orbital resonances with Jupiter over time. Once there, they are relatively rapidly ejected from the asteroid belt, tentative age estimates have been obtained for some families, ranging from hundreds of millions of years to less than several million years as for the compact Karin family. Old families are thought to contain few small members, and this is the basis of the age determinations and it is supposed that many very old families have lost all the smaller and medium-sized members, leaving only a few of the largest intact. A suggested example of old family remains are the 9 Metis and 113 Amalthea pair. Further evidence for a number of past families comes from analysis of chemical ratios in iron meteorites. These show that there must have once been at least 50 to 100 parent bodies large enough to be differentiated, when the orbital elements of main belt asteroids are plotted, a number of distinct concentrations are seen against the rather uniform background distribution of generic asteroids. These concentrations are the asteroid families, the proper elements are related constants of motion that remain almost constant for times of at least tens of millions of years, and perhaps longer

The asteroid belt is the circumstellar disc in the Solar System located roughly between the orbits of the planets Mars …

By far the largest object within the belt is Ceres. The total mass of the asteroid belt is significantly less than Pluto's, and approximately twice that of Pluto's moon Charon.

Johannes Kepler, who first noticed in 1596 that there was something strange about the orbits of Mars and Jupiter.

Giuseppe Piazzi, discoverer of Ceres, the largest object in the asteroid belt. For several decades after its discovery Ceres was known as a planet, after which it was reclassified as asteroid. In 2006, it was designated as a dwarf planet.

951 Gaspra, the first asteroid imaged by a spacecraft, as viewed during Galileos 1991 flyby; colors are exaggerated